Contrast enhancement of surface layers with fast middle-infrared scanning

Abstract

In this study, we present an efficient and innovative method to visualize absorption differences in the mid-infrared range with spatial resolution using laser technology. We focus on only two lasers with wavelengths between 3.4 μm and 3.6 μm and a spatial resolution of 20 μm and thus achieve a scanning speed up to 300 kS/s for fast image generation. In this article, we focus especially on the detection of C–H bands in this region of the absorption spectrum. Concealed structures are examined by calculating the measured structures with both wavelengths. In our results, we demonstrate exemplary measurements on 130-μm-thick polyvinyl chloride layers. In turn, these structures are suitable for further processing in rapid quantitative quality control.

Rapid brain structure and tumour margin detection on whole frozen tissue sections by fast multiphotometric mid-infrared scanning

“…The optical measuring system presented here consists of a flying spot scanner 34 – 36 . As previously published, the system is already designed to scan a sample surface with a non-contact technique 37 , 38 . Here the measuring system is based on two laser wavenumbers that are feasible for detection of long-chained C-H molecules.…”

“…The MIR scanner had four wavenumbers that were used for measurements. The individual wavenumbers were represented by Distributed Feedback (DFB) lasers (nanoplus Nanosystems and Technologies GmbH, Germany) that illuminated the sample depending on the measurement and necessity 37 , 38 . A lens system was used to focus the laser light onto the sample.…”